It is already known that if the static pressure of the deposit is larger than the sum of all the hydrocarbon pressure drops from the bottom of the well to its processing center, then the oil will naturally flow. However, if the static pressure is less than the result of the summation, some artificial production systems will be required.
The present invention refers to artificial production systems, which, as above mentioned, are used when the energy or pressure of the oil field is not enough to lift the fluids (oil-gas mixture) to the surface to be used by humans. In general, the artificial systems are classified into three big classes: mechanical pumping systems, pneumatic pumping systems, and electro-centrifugal systems.
The pneumatic pumping includes injecting a gas at a relatively-high pressure, in which the injected gas moves the fluids to the surface to reduce the pressure exerted by the fluid, expansion of the injected gas, or fluid displacement.
The pneumatic pumping is flexible, both in its configurations, as well as in the capacity it controls, is able to manage sand within the well, does not need much space for the facilities in surface, and with a single system several wells can be fed, and additionally, does not require modifications to the finished well for any type of variations, as it actually happens in the mechanical pumping, electro-centrifugal pumping, and progressive cavity.
The present invention relates to the field of pneumatic pumping with the patentable characteristic to be movable and to be adapted to the available space in the wells.
Following patent applications and patents related to the present invention are known.
U.S. Pat. No. 3,215,087 provides a new and improved system for the artificial gas lifting. In accordance with what is described by this patent, it was found that the lift efficiency may be improved through the intermittent injection of a viscous and immiscible fluid with the fluid that is intended to be recovered from the well, being displaced with gas coming from the well or from an external source through the annular lining-priming, passing through a valve (22) to the inside of the priming, and not from a pneumatic pumping system (BNA) self-supplied and continuous as in the present invention.
This patent discloses that fluids used for purposes of the invention are solutions that are practically immiscible with the fluids produced or extracted from the well, that do not adhere to casings, piping, and other equipment from which the fluids come into contact and that have enough viscosity to resist the cut during the flow. In the case where the fluid produced is crude oil, an aqueous solution that contains a polysaccharide, a poly-acrylamide, sulphonated aromatic poly-vinyl is used, or a soluble water thickener or water dispersant, in a concentration enough to produce a practically superior viscosity to the one of the crude oil, which is not the case in the present invention.
The MX Patent 43214, entitled “Method for Producing Oil from Partially Exhausted Wells” filed on Jun. 3, 1944, which is the closer state of the art and that shows the following differences regarding the present application:
a) The patented process is in the field of improved secondary recovery (EOR) while the one of the present application, hereinafter called as BNA system, (self-supplied pneumatic pumping) is an improvement of the pneumatic pumping as a system of artificial production (SAP);
b) In the patented process of the vapor fractions, injection recovered by means of distiller equipment and distillation columns are injected to a well for improving the viscosity of the oil of the entire oil field and that the rest of the wells improve their production through this action, positioning this invention in the oil recovery system.
The U.S. Pat. No. 4,666,377 entitled “Method and Lift Pump and Raising Liquids” refers to an apparatus and specifically it is related to a sub-superficial pump, submerged at approximately 50% of the fluid column contained in the well, and uses liquid such as motor fluid and not gas as in the present invention. Additionally, the use of auxiliary systems in this disclosure is missing.
The U.S. Pat. No. 5,006,046 entitled “Method And Apparatus For Pumping Liquid From a Well Using Wellbore Pressurized Gas” is based on the insertion of a pipe inside a well liner to extract oil from the bottom, by injecting pressurized gas in cyclic form and controlled by means of a sensor to measure the liquid level and a controlling valve at surface that enables gas going through the well and pushes the oil to the surface. This patent remarkably differs from the present invention since it is based on a continuous operation system and does not indicate the use of separation and compression gas equipment, so it needs an external source to provide gas under pressure.
The U.S. Pat. No. 6,298,918, entitled “System For Lifting Petroleum By Pneumatic Pumping” involves the development of an apparatus and procedure for the application of a fluid accumulation camera inside a well and the injection in cyclic form of a gas under pressure to displace the oil to the surface, which differs from the present invention in that, it does not use any equipment to store fluids inside the well and that also requires, as specified, that they require gas under pressure as an external source.
The U.S. Pat. No. 6,354,377 entitled “Gas Displaced Chamber Lift System Having Gas Lift Assist” comprises in a modification of the previous patent and among main changes, there is the inclusion of a second liquid accumulation camera in the bottom of the well and a multi-stage compressor with a capacity of providing a pressure higher than 5,000 psi to inject gas to the chambers. It is not specified, but it is required, that a source of external gas under pressure and the process is also cyclically differing from the present invention.
The U.S. Pat. No. 7,147,059 entitled “Use Of Downhole High Pressure Gas In a Gas-Lift Well And Associated Method” consists on the application of equipment and methods to isolate and use the high pressure gas zones of a well as high pressure supplying sources are to be used as continuous pneumatic pumping. The difference is obvious to the present application, since it does not use gas associated with the production of oil, or any of the separation and compression equipment.